Lubricant, grease and hydraulic fluid

ABSTRACT

Lubricants, greases and hydraulic fluids are described which consist of, or comprise as an essential constituent substituted imidazolidin-2-ones or pyrimidin-2-ones. A preferred lubricant contains 69 percent to 77 percent of N,N&#39;&#39;didodecylimidazolidin-2-one and 31 percent to 23 percent of N,N&#39;&#39;di-octyl-5-methylimidazolidin-2-one.

United States Patent Inventor Joachim Dazzi Riehen/Basle, Switzerland Appl. No. 827,880 Filed May 26, 1969 Patented Sept. 28, 1971 Assignee Geigy Chemical Corporation Ardsley, N.Y. Priority May 29, 1968 Switzerland 7972/68 LUBRICANT, GREASE AND HYDRAULIC FLUID 8 Claims, No Drawings u.s. Cl 252/475, 252/495,252/491,252/495,252/49.9,252/51.5

R, 252/515 A, 252/77, 260/251 R, 260/309.7

Int. Cl Cl0m 1/38,

[50] Field of Search 252/49.6, 51.5, 5 L5 A, 49.9, 49.7, 77, 47.5, 49.8

[56] Relerences Cited UNITED STATES PATENTS 3,218,258 ll/l965 Bauer et al 252/5L5 3,301,784 l/l967 Anderson 252/515 Primary Examiner-Daniel E. Wyman Assistant ExaminerW. Cannon Attorneys-Karl F. Jorda and Martin J. Spellman ABSTRACT: Lubricants, greases and hydraulic fluids are described which consist of, or comprise as an essential constituent substituted imidazolidin-Z-ones or pyrimidin-Z-ones.

A preferred lubricant contains 69 percent to 77 percent of N,N'-didodecylimidazolidin-2-one and 31 percent to 23 percent of N,N'-di-octyl-S-methylimidazolidin-Z-one.

LUBRICANT, GREASE AND HYDRAULIC FLUID DESCRIPTION OF THE INVENTION The present invention concerns the use of compounds of the formula I,

R1-N N-R) 0 G ii 1 2 as lubricant, grease and/or hydraulic fluid whereby X represents $H3 i i -c H,cH,-, CH,OH, -cH,- H or CH,OH CH R represents a straight-chained alkyl radical having 1 to 18 carbon atoms and R represents a straight-chained alkyl radical having 6 to 18 carbon atoms,

and the sum of the carbon atoms contained in R and R amounts to at least 12 and at most 30, but preferably not more than 24.

The compounds of the formula I, according to the invention, can also be a constituent of compositions of matter, e.g. used together with mineral or synthetic lubricating oils or other hydraulic fluids, which also contain the usual additions such as antioxidizing agents, thickeners, pour-point depressants, high-pressure additives and/or anticorrosion agents.

Very high requirements have to be met by lubricants and hydraulic fluids, such as are used in modern machines and equipment, e.g. in gas turbines of aircraft engines, for exampie:

1. they must be fluid under the conditions of application and must be able to form a lubricating film on the widest range of materials, especially on metals,

2. they must have low volatility and be highly thermostable,

3. they should have no corrosive action and, above all, they should form no acid decomposition products,

4. they should retain their lubricating properties over as wide as possible a temperature range, i.e. their viscosity should be as little as possible dependent on the temperature,

5. they should have the lowest possible solidification point and, on the other hand, the highest possible boiling point.

In addition to these requirements, the lubricants and hydraulic fluids must be compatible with rubber, metals and plastics, as well as resistant to oxidation and hydrolysis; moreover they must have a high flashpoint.

Many of these essential properties cancel each other out and it is therefore difficult to find materials which fulfill all these requirements to such an extent that they are, for example, suitable for gas turbines.

For example, the following types of compounds have been hitherto used as lubricants and/or hydraulic fluids:

a. high boiling, organic esters such as diesters of dicarboxylic acids, e.g. adipic acid or sebacic acid, with alcohols having a medium to long carbon chain, also triesters of trimethylol propane and higher fatty acids or esters of pentaerythrite and monocarboxylic acids of average chain length;

b. inorganic esters, e.g. orthophosphoric acid esters of organic hydroxyl compounds, especially alkyldiaryl phosphates or trialkyl phosphates; 7

aromatic ethers, especially polyphenyl ethers having 3 to 6 phenyl rings;

d. polyalkyl melamines;

e. silicon compounds, such as silicone oils or silicates, e.g.

tetraalkyl orthosilicates, or hexaalkyloxydisiloxane;

f. N-alkylcyclohexane-l ,Z-dicarboxylic acid imides.

Surprisingly, it has now been found that the heterocyclic compounds of the formula I, usable according to the invention, are suitable as lubricants, as lubricating greases and hydraulic fluids. This is all the more surprising since it is know from the literature (Ullmanns Encylclopaedie der technischen Chemie, 3. Edition, Vol. 15, p. 307, (I964 Publishers Orban and Schwarzenberg), that the lubricating properties of the urea derivatives so far investigated, are unsatisfactory.

The compositions of the present invention are particularly valuable in a mixture as follows:

from about 25 percent to 99.99 percent of a compound of formula I,

b. from 0.0l about 5 percent of an additive such as antioxidants, pour-point depressants, antifoaming agents, anticorrosion agents and high-pressure additives or mixtures thereof,

c. from 0 percent to about 75 percent of a lubricant and d. from 0 percent to 75 percent of a thickener.

The N,N-dialkylimidazolidin-Z-ones and N,N'-dialkylhexahydropyrimidin-2-ones of the formula I are in some cases known and can be produced according to processes known per se. They can be produced, for example, according to W. R. Boon, J. Chem. Soc., pp. 307, (1947 by treatment of the diamines with phosgene. Preferably however, the compounds of the formula I are obtained according to A. E. Martell and A, E. Frost, J. Amer. Chem. Soc. 72, 1032-1033, (1950) by heating N,N-dialkylalkylene diamines with a small excess of urea without solvent with the evolution of ammonia. With this process, the yields are around percent. In this process, it is advantageous if the N,N-dialkylalkylene diamines, e.g. produced according to J. Org. Chemistry 14, 948, (1949 are as pure as possible. To produce the N,N-dialkylalkylene diamines from alkylene dichlorides and primary amines, commercial primary amines are used which, for example, in the case of the decyl or octyl amine, are used as a mixture of primary alkylamines with the alkyl radical having an average number of carbon atoms of 10 or 8.

Very favorable lubricating properties, especially in admixture with the usual lubricants such as organic esters, polyaryl ethers, high-boiling mineral oils and certain silicone oils, are exhibited by those N,N'-dialkylimidazolidin-2-ones and -hexahydropyrimidin-Z-ones, whereby the number of carbon atoms of the dialkyl radicals, i.e. the sum of the carbon atoms of R and R in formula I, is at least 12 and at the most 30. As lubricants and hydraulic fluids, those compounds of the formula I are preferred, wherein the sum of the carbon atoms of R and R is between 16 and 24. Particularly good lubricating properties and a favorable pour point are possessed by the N,N'-dialkylimidazolidin-Z-ones and -hexahydropyrimidin-2- ones, which in addition to this condition have been obtained, as already mentioned, from a commercial mixture of various primary alkylamines.

Compared with hitherto known products, used as turbine lubricating oils, the compounds of the formula I, usable according to the invention, are characterized by a particularly good thermostability. They have not decomposed even after a period of 2 hours at 380 C., whereas the hitherto most thermostable organic esters, e.g. the triesters of fatty acids with trimethylol propane, are unusable after 2 hours at temperatures from 360 C. A further advantage of the compounds of the formula I, compared with lubricants based on organic or inorganic esters, is that, in contrast to the esters, they form practically no acid decomposition products in the case of thermal decomposition. The low tendency of the N,N-dialkylimidazolidin-2-ones or N,N-dialkylhexahydropyrimidin-2 ones to form acid decomposition products, which are responsible for the corrosion action, is shown by the fact that the volatile compounds and also the residue formed, e.g. by the exposure for 6 hours of N,N-didodecylimidazolidin-Z-one or N,Ndidecylimidazolidin-2-one to a temperature of 380 C. under a nitrogen atmosphere, are neutral whereas the substances which are formed from the triester of trimethylol propane and pelargonic acidat 360 C. in a nitrogen atmosphere, have a combined acid number for volatile fractions and residue of around 78 mg. KOH/g.

A further advantage of the compounds of the formula 1, to be used according to the invention, is that, for example, a mixture of 73 percent of N,N'-didodecylimidazolidin-Z-one and 27 percent of N,N'-dioctyl-5methylimidazolidin-Z-one at 210 F. (98.8 C.) has a viscosity of 5.0 centistoke (c St) and thus satisfies the specification of the Pratt and Witney-Tests Type 11. The solidification point too is lowered with application of this mixture.

Compared with the, in some cases, very thermostable silicone oils and polyphenyl ethers, the compounds of the formula I, to be used according to the invention, are characterized by a better lubricating effect and, compared to polyphenyl ethers, also by a lower pour point, a more favorable temperature viscosity relationship, as well as a lower density.

The compounds of the formula 1, usable according to the invention, are suitable for lubricating the most varied types of surfaces. Thus they appreciably reduce the friction of metal on metal, but they also reduce the friction of metal on silicate, such as glass.

A further advantage of compounds of the formula 1, usable according to the invention, is their surprisingly good miscibility with other common hydraulic fluids and lubricants, e.g. with those based on organic esters, polyaryl ethers, polyalkyl melamines, high-boiling phosphoric acid esters, high-boiling mineral oils, N-alkylcyclohexane-1,2-dicarboxy1ic acid imides, certain silicone oils or orthosilicates. This favorable miscibility renders possible the production of special lubricants in that the properties required, but not attainable by means of the separate components, for a specific application, can be obtained by producing suitable mixtures.

To the compounds of the formula I, to be used according to the invention, can also be added additives for improving or modifying the properties such as antifoaming agents, agents which lower the pour point and thickeners. The usual additives such as phosphites, phosphates, sulphurized sperm oil, are suitable as high-pressure additives in lubricants or hydraulic fluids, usable according to the invention. The N,N' -dialky1imidazolidin-2-ones and -hexahydropyrimidin-Z-ones, usable according to the invention, can also contain antifoaming agents, e.g. such as are based on silicone oil.

Compositions of matter fluid at room temperature which, according to the invention, can be used as lubricant or hydraulic fluid having a thermal stability of at least 360 C., contain at least 25 percent by weight, relative to the total weight ofthe composition of matter, of compounds of the formula 1, and up to 75 percent by weight of at least one hydraulic fluid or one lubricant based on esters, aromatic ethers, silicon compounds, N-alkylcyclohexane-1,2-dicarboxylic acid imides, melamines and high-boiling mineral oil fractions. The specific mixture ratio used depends on the purpose of application.

Furthermore, the invention also embraces greases consist ing of compounds of the formula 1 and thickeners. Examples of suitable thickening agents are metal soaps, bentonites, phthalocyanines, violanthrones, graphite.

The following examples illustrate the special suitability of the N,N'-dialkylimidazolidin-Z-ones and -hexahydropyrimidin-Z-ones used, according to the invention, as synthetic lubricants and as hydraulic fluids. The units of measure of the metric system are used in the examples and, where not otherwise mentioned, the temperatures are given in degrees ccntigriule.

a. 57 g. of N.N'-dioctyl ethylene dinminc (0.2 mol) and g. of urea (0.25 mol) in a three-necked flask, fitted with cooler, thermometer and inlet tube for nitrogen, are heated within 6 minutes, using a direct flame, to 300. A great amount of ammonia is split off from 250 and at about 300 the reaction has then ceased. Four further analogous starting mixtures are treated together by filtering off the reaction mixture at 50 from high-melting byproducts. The filtrate is treated with diluted acetic acid and then made alkaline with 50 ml. of IN sodium hydroxide solution. It is then thoroughly washed three times using, each time, 300 ml. of water, dried and then fractionally distilled. By this means are obtained 24 g. of first runnings, b.p. l50 under 0.001 Torr and 227 g. ofa main fraction, b.p. l50-l52 under 0.001 Torr. After distilling twice, the N,N-dioctylimidazolidin-Z-one n 1.4666; density 0.91 are obtained in 78.3 percent yield (calculated on the basis of the N,N'-dioctyl ethylene diamine used).

b. Analogously to example la), 29.9 g. of N-butyl-N'- dodecyl-l,3-propylene diamine (0.1 mol) with 7.5 g. of urea are heated quickly to 300 until, after 9 minutes, the splitting off of NH ceases. The reaction mixture is diluted with 50 ml. of toluene, filtered off from insoluble solid byproducts and the filtrate washed acid, and also alkaline, fractionated. b.p. 163 under 0.005 0.007 Torr. By this means were obtained 23.0 g. of N-butyl-N-dodecylhexahydropyrimidin-Z-one, n 1.4730 in a 70.9 percent yield.

c. The remaining compounds of the formula 1, to be used according to the invention, are produced in a similar manner, or according to the production process of A. E. Martel! and A. E. Frost, J. Amer. Chem. Soc. 72, 1032-33 1950 The N,N'-dia1kyla1ky1ene diamines, used as starting material for synthesis of the N,N'-dialkylimidazolidin-2-ones or -hexahydropyrimidin-Z-ones, are produced analogously to the specification in J. Org. Chemistry 14, 948 (1949 Example 2 In table 1 is contained the physical data of some N,N-dia1- kylimidazolidin-Z-ones and -hexahydropyrimidin-Z-ones, which clearly shows the suitability of these stable and difficulty volatile compounds of the formula 1 as a hydraulic fluid or lubricant. 1n column 3 is given the viscosity, measured in centistokes, at 100 F. (37.8 C.) and at 210 F. (98.8 C.).1n column 4 is given the figure known as the ASTM-Slope," which is calculated mathematically from the viscosity values determined at 100 F. or 210 F., using the "ASTM Standard Viscosity Temperature Chart for Liquid Petroleum Products" (Method D 341 The lower the numerical value of this ASTM-Slope of a fluid, the more suitable it is as a lubricant. A value of over 1.0 means that the fluid concerned has very little suitability. ASTM is the abbreviation for American Society for Testing Materials, 1961 Race Street, Philadelphia, Pa. USA.

In column 5 is contained the viscosity index which is likewise calculated from the viscosity values determined at 100 F. or 210 F. The method for calculating the viscosity index can be found, for example, in Standard Methods for Testing Petroleum and its Products," The Institute of Petroleum, 61 New Cavendish Street, London, W.1, Eighteenth Edition, 1959, pages 734-739. The higher the numerical value in column 5, the more suitable is the substance as a lubricant. A value of below 100 that the fluid concerned has little suitability. But the ASTM-Slope and the viscosity index are empirical values, which describe the temperature dependence of the viscosity of a lubricant. The corresponding values of some commercial lubricants have been given for the purpose of comparison.

TABLE I Compound of Formula I TAB LE IContinued Compound of Formula I X Viscosity in est. m ASTM Vis- No. Ill-N N-Rg 100 F. 210 F. slope cosity (37.8) (983) index C 3 HnCaN NCsHir 16.0 3.47 0.765 104 C ii 0 4 HnCmN NCmHgi 21. 2 4.5 0.70 145 C ll 0 5 HgsCxgN N C I-I23 30. 8 5. 92 O. 68 144 6 ILsCzN NCisHu 28 5. 67 0. 66 150 7. llz cmN NCwHg 21.8 4.39 0.73 128 C H O C2Hs 1 8. IIUCEN NCgHn 17. 0 3. 60 0. 76 104 l 9... IIQCIN NCnHzs 16.3 3.63 0.74 120 i 'l 10. HsClN NCisHn 32 6. 20 0. 60 150 C ll 0 11.. H9C4N NCizHas 12.. Mixture of 73% Compound 25. 3 5.0 0.69 138 N0. 5, 27% Compound No. 3.

(ommorcinl or similnr lubricants l3 2,4,6trls-riilmi vl nmino-s- 131. (1 12. 64 0. 7 95 trlnzluv. l4 Mineral nil (Mobil DTE 115. 7 8.4 0. 71 106 11 it). 15 1.,4-lls-(i1ilmtylamlno)-ti- 134 15. 0 0. 64 122 (1idodocyl-mniuos trinzinv. 113.. N-iHlocyl-cis-cyclohcxano 32. i1 4. 8 0.81 68 1,2-dicarboxylic acid imidc. 17. 1)i-2-r-tliyll1oxyl-sobaeate 12. 3. 3 0.7 154 (commercial product). 18. lontaphonylothor 361) 13. 5 0. 89 75 mixturev (commercial product: 08-124, Monsanto Chem. Co. St. Louis. U.S.A.).

EXAMPLE 3 N,N'didodecylimidazolidin-l-one is suitable for the lub'rication of metal surfaces. To obtain a quantitative comparison of its lubricating action compared to some similar and to some commercial lubricants, the diameter of the wearing calotte in a precision 4-ball apparatus was measured. These measurements were carried out in accordance with the US Federal Specifications Lubricants and Related Products VV-L 79 1e. Method 6503 Load Carrying Capacity (means Hertz Load)." This apparatus ran for 30 minutes at a speed of 1480 rotations per minute with a loading of 40 kg. and using /2-inch steel balls SKF A-quality and with an initial temperature of ca. 40. in the case of the compound 1 in table 11, on the other hand, the N,N -didodecylimidazolidin-Z-one was measured at 70.

The results are contained in following table 11.

TABLE 11 Diameter of the Viscosity in cst. wearing calotte 100 F 210 F No. Substance used in mm 1 (37.8") (983) 1.. N,N-didodecyl-infidazolidin-Z- 0 61 30.8 5. 92

one. 2. Di-Z-ethylhexyl sebacate 0.85 12. 7 3. 3 3. Mineral oil (Mobil DTE light). 0.90 65.1 8.4 4. Pentaphenylether (OS-124, 1.15 369. 5 13.50

Monsanto Chem. 00., St. Louis, U.S.A.). 5. Methylphenyl silicone (MS 550 2 1. 9 78. 3 19.

der Midland Silicones Ltd., England). 6. 2,4-bis-(dibutylamino)-6- 0. 60 104. 1 J. 8.5

diethylamine-s-triazine. 7. 2,4-bis-(dibutylamino)-6- 0.55 134. 0 15.0

didodecyl-amino-s-triazine.

1 Average of 3 measurements.

The N,N'-dialkylimidazolidin-Z-one of table 1, No. 2,3,4 and 6, and the N-butyl-N-dodecylhexahydropyrimidin-Z-one produce, in this lubrication test, similarly good results to the N ,N'-didodecy1imidazolidin-Z-one given in table 11.

EXAMPLE 4 In order to be able to adjust the properties of lubricants and hydraulic fluids to be suitable for any desired application, it is important that they be miscible with other lubricants or hydraulic fluids. in order to test the behavior, in this respect, of the compounds of the formula 1, be used according to the invention, their miscibility at 25 with various commercial lubricants and hydraulic fluids was examined. The viscosity in centistokes of the mixture concerned was determined at 100 F. (378) and at 210 F. (98.8") and the figures obtained are given in column 3 of table 111. The ASTM-slope is given in column 4. In column 1 is shown the second component of the mixture and in column 2 is given the mixture ratio with N,N- didecylimidazolidin-Z-one. The corresponding data for the pure unmixed N,N-didecylimidazolidin-Z-one is given at the end of table 111.

TABLE III Mixture ratio olitlin- Suhst. 100 1*. 210 F. .481)!- Substance X Z-onc X 7.8") (085) slope 0 100 .33. 7 -i. .i 11, T0 Trimotliyl piopnno 33 67 23. 0 4, 7'1 0. 70 tlipcllni'gmintv. 50 50 l2. 4 -i. 0. (i7 33 11.8 4. -17 11.70 I (l 101) 1'1. 7 3. 30 0, T0 1)i 2-ot1i vllu-xyl- 33 11'. ii. 1 3. (I 0. 70 Stl1t1t111.0 so so .5 a. 0. 7o 67 33 17. 0 3.115 0. T0 0 8 4. 10 0. ST v 33 e7 25. 4 4. 20 0. s1 Tn-cresylpliosphate 5O 50 24' 0 4' 30 0. 67 33 2'2. 6 4. 40 0. H Pentaphenylether 0 100 360 13. 5 0. 89 (OS-124, Monsanto 33 67 81 T. 3 0. 83 Chem. Co., St. 50 50 48 6. 05 0. 71 Louis. U.S.A.). 67 33 33 5. 3 0. 75 0 100 65. 7 8. 4 0. T1

Mineral oil SAE 33 67 43 6. 65 0. T

(Mobil DTE light). 50 50 35. 5 6.0 0. T0 67 33 29. 5 5. 4 U. 70

TABLE lll Continuerl Mixture ratio N ,N- dldecyl Viscosity in est. imidazolidin- Subst. 100 F. 210 F. ASTM- Substance X QFOne X (37.8) (98.8") slope 2,4-bis-(dibutyl- (l 100 134 15.0 0. 64 amino)-6-dodo- 33 67 T 9. 2 0. 68 decylamino-s- 50 t) 50 7. 5 t). 69 triazine 67 33 36. 5 6. 2 t). 70

O N-decylcyclohexaneg 89 2 1,3 1,2-dicarboxylic 50 6 5 acid imidt: 67 33 24.4 4. 57 0. 73 Silicone oil 550 g glfiltllan l nilitons 5O 50 37 2 7.43 0.61 67 33 29.9 6.10 0.64 N..\"- lidt.-r:ylimitl aZol.tlin-2-0ite 100 0 21.2 4. 50 0.70

The N,N'-didecylimidazolidon-Z-one is miscible at 0 as well as at 25, in any proportion, also with a bis-(phenox yphenyl)-ether (e.g. Dow ET-378 of the Dow Chemical Co. Midland Mich. U.S.A.), as well as with tetra2-ethylhexyl silicate and methylphenyl silicone oil (e.g. Silicone DC 550 Fluid of The Dow Corning Co. Midland Mich. U.S.A. or Silicone MS 550 of the Midland Silicons Ltd.), and also with 2,4- bis-(dibutylamino)-6-diethylamino-s-triazine.

EXAMPLE 5 To produce a lubricant or hydraulic fluid containing an antioxidant, 98 g. of N,N-didecylimidazolidin-2-one are mixed by stirring with 2 g. of di-tert.octyldiphenylamine as an antioxydant, until the latter has completely dissolved. The obtained mixture, compared with that containing no antioxydant, exhibits an increased resistance to oxidation.

In the same manner, the other compounds given in table I can also be made more resistant to oxidation.

if one of the antioxidants given below are used in place of the 2 g. of di-tert.octyl-diphenylamine, with otherwise the same procedure, the resistance to oxidation the N,N' -dialkylimidazolidin-2-ones or -hexahydropyrinidin-2-ones is likewise increased:

didodecylselenide,

l l ,3-tri-(2 '-methyl-4 -hydroxy-5 -tert.butylpl'tenyl)-butane,

2,6-di-tert.butyl-4-methyl-phenol,

2-tert.octylimino-dibenzyi or S-ethyl-l0,lO-diphenyl-phenosilazine.

EXAMPLE 6 97 g. of N,N'-didecylimidazolidin-2-one are homogeneously mixed, by stirring, with 3 g. of polymeric methacrylic acid ester, e. g. poly-Zethylhexyl-methacrylate (HF 825 of Fa. Rohm and Haas Co., Philadelphia, U.S.A.). This mixture has a lower pour point than the compound not containing this active substance. W

The remaining N,N-dialkylimidazolidin-Z-ones or the -hexahyclropyrimidin-2-one, given in Table I, also behave similarly.

EXAMPLE 7 it 97.8 g. of N,N-didecylimidazolidin-2-one are mixed with 2 g. of di-tert.octyl-diphenylamine as antioxidant, and with 0.2 g. of henztrinzole as an anticorrosion agent, a lubricant is obtained which exhibits lower sensitivity to oxidation and lower corrosivity than :1 corresponding lubricant not contnining the stated nctive substances.

Similnt results can also be obtained with the remaining N,N-diulkylimidazolidin-2-ones or with the -hexahydropyrimidin-2-one, which are contained in Table l.

EXAMPLE 8 The applicability of the N,N -diaikylimidazolidin-2-ones or N,N-dialkylhexahydropyrrolidin-2-ones, according to the invention, for the production of lubricating greases is shown in the following example.

Eight grams of copper phthalocyanine are very rapidly stirred for 15 minutes with 4 g. of compound No. 4 in table I and 40 ccm. of benzene in an Ultraurax-mixer. A further 20 g. of this product No. 4 are then added and the mixture is very rapidly stirred for a further 45 minutes.

The thus obtained homogeneous mixture is kneaded with a spatula on a glass surface until the benzene has evaporated. The mixture is heated during 2 hours to and, after cooling, again kneaded with the spatula. Thus obtained product is a soft, easily workable lubricating grease, on which the following lubricating properties were measured: Penetration.ASTM D. 1403-56 T (Edition 1958). Linworked: 035; worked: 328.

Dropping point.ASTM D. 566-42 (lP. 131/57) (Edition 1957), worked; 238. r 7 mm. Similar results are obtained if the compounds given in table I are used.

EXAMPLE 9 To produce a lubricant containing antioxidant, anticorrosion agent and high-pressure additive, 94.8 g. of N,N'- didecylimidazolidin-Z-one are mixed with 2 g. of di-tert.octyldiphenylamine as an antioxidant, 0.2 g. of benztriazole as an anticorrosion agent and 3 g. of trikresyl phosphate as a highpressure additive. A lubricant is obtained which exhibits a lower oxidation sensitivity and lower corrosivity and which withstands higher compressive loads than the corresponding lubricant not containing the stated active substances.

Similar results are obtained in the N ,N- didecylimidazolidin-Z-one is replaced by one of the compounds Nos. 1 to 3, or 5 to ll, or mixture No. 12 of table I, and when it is mixed with antioxidants, anticorrosion agents and high-pressure additives to the extent of 001-5 percent, calculated on the total weight of the composition.

EXAMPLE 10 99 g. of N,N'-didodecylimidazolidin-2-one and l g. of iminodibenzyl are mixed together until the latter has completely dissolved. The obtained mixture exhibits, compared to the pure N,N-didodecylimidazolidin-Z-one, an improved oxidation stability.

Similar results are obtained if the other compounds of formula l in table I, applicable according to the invention, are mixed with the appropriate antioxidants, which are commonly used commercially, in quantities of 0.0l percent to 5 percent relative to the N,N'-dialkylimidazolidin-Z-one which is to be made stable to oxidation.

EXAMPLE 11 99.8 g. of N,N-dioctylimidazolidin-2one and 0.2 g. of benztriazole are mixed. The obtained mixture possesses, compared to the pure compound of the formula I, a lower corrosion action, particularly in the case of copper and its alloys.

Similar results are obtained if the other compounds of the formula I in table I, usable according to the invention, are mixed with 0.2 g. of benztriazole and then examined with regard to their corrosion action.

EXAMPLE l2 97.5 g. of N',N-didodecylimidnzolidin-Z-one. l.5 g. ol'dibutyl phosphite and l g. of phenyl-a-nuphthylamine are mixed by stirring. The obtained mixture exhibits, compared to the pure N,N'-didodecylimidazolidin-2-one, an improved oxidation stability and a better lubricating-film load capacity.

Similar results are obtained if the other compounds of the formula l in table 1 are mixed with appropriate high-pressure additives and antioxidants in quantities of 0.0l percent to 5 percent, relative to the N,N-'-dial;kylimidazolidin-2-one or the -hexahydropyrimidin-2-one which is being made resistant to oxidation.

lclaim:

1. A composition comprising:

a. a compound of formula I Il -N WhCTCIH X is Um R is alkyl offrom l to 18 carbon atoms; R is alkyl of from 6 to 18 carbon atoms,

the sum of all carbon atoms of R, and R being at least 12 and at most' 30; said compound being used in the range from about e. a lubricating oil in the range from 0 to about 75w/o; and

f. a lubricating oil thickener in the range from 0 to about 2. A composition as defined in claim 1, wherein the lubricant is selected from organic acid esters, polyarylether, polyalkyl melamines, N-alkyl-cyclohexane-l, 2-dicarboxylic acid imides, high-boiling phosphonic acid esters, high-boiling mineral oils, silicone oils and orthosilicates.

3. A composition as defined in claim 1, wherein component (a) is a mixture of:

N,N'-didodecylimidazolidin-Z-one and N,N'-dioctyl-5-methylimidazolidin-2one, the former being present in an amount of from about 69 percent to 77 percent and the latter in an amount of about 31 percent to 23 percent, these percentages being by weight calculated on the total weight of the composition.

4. A composition as defined in claim 1, wherein said component (a) is N,N'-dioctylimidazolidin-2-one.

SJA composition as defined in claim 1, wherein said component (a) is N,N-didecylimidazolidin-2-one.

6. A composition as defined in claim 1, wherein said component (a) is N, N'-didode?ylimidazolidin-2-one.

7. A composition as de med in claim 1, wherein said component (a) is N,N-dioctyl-5-methylimidazolidin-2-one.

8. A composition as defined in claim 1, wherein said thickener is copper phthalocyanine. 

2. A composition as defined in claim 1, wherein the lubricant is selected from organic acid esters, polyarylether, polyalkyl melamines, N-alkyl-cyclohexane-1, 2-dicarboxylic acid imides, high-boiling phosphonic acid esters, high-boiling mineral oils, silicone oils and orthosilicates.
 3. A composition as defined in claim 1, wherein component (a) is a mixture of: N,N'' -didodecylimidazolidin-2-one and N,N'' -dioctyl-5-methylimidazolidin-2-one, the former being present in an amount of from about 69 percent to 77 percent and the latter in an amount of about 31 percent to 23 percent, these percentages being by weight calculated on the total weight of the composition.
 4. A composition As defined in claim 1, wherein said component (a) is N,N'' -dioctylimidazolidin-2-one.
 5. A composition as defined in claim 1, wherein said component (a) is N,N'' -didecylimidazolidin-2-one.
 6. A composition as defined in claim 1, wherein said component (a) is N,N'' -didodecylimidazolidin-2-one.
 7. A composition as defined in claim 1, wherein said component (a) is N,N'' -dioctyl-5-methylimidazolidin-2-one.
 8. A composition as defined in claim 1, wherein said thickener is copper phthalocyanine. 